When Trish Barillas’ fiancé, Charlie Sandlan, is at risk of getting on her nerves — for example, by chewing loudly, protesting girls’ night or trashing her new favorite hip-hop song — she can shut it down in a word.

“I just say, ‘contract,’ and we kind of return to a natural calm state,” says the 40-year-old life coach.

Barillas and Sandlan, who have been together for a year and a half, have a relationship contract — a smartly designed, 22-item pact enumerating their desires and pet peeves.

Break the terms, Barillas says, and they’ll have to take a good, hard look at their courtship.

The Chelsea couple, now engaged, drafted up their pact a mere 15 days after their first date. Sandlan, 48, had read about them online and brought the idea up with Barillas during a drive upstate. She was immediately on board.

“Relationships get messy and confusing,” says Barillas. “Contracts are reliable — very crystal clear and concrete.”

Control-loving New York couples are jumping on board with prenups for dating, that lay out everything from sex goals to off-limits fighting strategies to non-negotiable personal quirks. Lovers who sign on the dotted line claim that the contracts encourage rational boundary setting, fair fighting and compromise.

For Barillas, that means starting her days on a less-than-ideal note. “I hate NPR,” she says. But Sandlan loves to have it playing in the background when he’s getting ready for his day.

“So [he stipulated that] in the mornings, he has to listen to NPR for at least 20 minutes,” she says. For the good of the couple, Barillas says, “I agreed.”

She’s also given him football Sundays, two date nights a week and a daily phone call — lasting at least five minutes.

“Normally, I would have felt suffocated” by that much contact, she says. But the contract helped to take the edge off. “This is just what he likes — [it’s not] about something I did wrong.”

Besides, she points out, Sandlan has made equally important concessions for her: He’s contractually obligated to support her yearly trips with her best buds, to let her pay for things once in a while and, yes, to work on not chewing loudly.

Relationship therapists say that contracts like Barillas and Sandlan’s can be helpful — depending on how they’re written.

“A long laundry list of annoyances in the form of contractual obligations is not going to fix the relationship,” says Jean Fitzpatrick, a Murray Hill-based marriage counselor who works on similar agreements with her clients, usually during premarital counseling. She believes the trend toward dating contracts likely stems from young couples wanting to split up tasks differently than their parents’ generation did.

The “emotional prenups” Fitzpatrick works on with her clients focus on problems that would necessitate a return to counseling, such as an ongoing conflict or someone not doing their share of chores.

But some think a breach isn’t even worth renegotiating. For Amy Chan, a 37-year-old Chelsea resident, a relationship-contract dispute was reason enough to call it quits.

“It didn’t work because we couldn’t agree on our terms,” says Chan, who runs a retreat called Renew Breakup Bootcamp for women who are trying to recover from a bad split. She felt like, for her ex, “everything had a disclaimer or an ‘out,’ ” allowing him to weasel out of his responsibilities and promises he’d made to her.

‘Relationships get messy and confusing. Contracts are reliable — very crystal clear and concrete.’

About a month ago, Chan met a new guy. They’ve already drafted a few points on their contract. Among her demands: At least once a year, they’ll each take a trip without one another to “prevent co-dependence.” Whoever cooks, the other person cleans. Her partner will kill spiders. When traveling, they must video chat every couple days. At least once a week, they must give each other massages.

“We expect our partners to read our minds, but we’re not clearly articulating these things,” says Chan. “It seems unromantic to have these conversations . . . But you can rely on [these contracts] when you’re angry, emotional or projecting past baggage, and you can use [it] to guide you through those times.”

Even married couples can stand to benefit from a relationship contract, says Andrew Kippen. The 37-year-old hypnotherapist from Clinton Hill and his wife, Nyla, decided to draft up a contract in January — 1 ¹/₂ years after they tied the knot. Kippen had experimented with an “intimacy contract” with another woman in the past, which helped him establish some specific terms for their friends-with-benefits-style situation. It had helped them communicate, and he felt that it might be a good thing for his new marriage, too.

His and his wife’s 30-item contract focuses mostly on their long-term hopes for their marriage. (“I’m in the process of memorizing them,” Kippen says.) Some items are general, like working through arguments with “compassion and empathy.” Others are aspirational: “We look sexy for each other.”

Kippen and his wife keep their contract on their bedside table and try to review it every day.

“When I’m deciding whether I’m going to put on sweats or take a shower and trim my beard and put on moisturizer, I’m going to do the latter because of the contract,” he says.

“It’s like having the bumpers up on the bowling lane — it gives us structure,” he says. “It keeps me focused on where we’re headed and what we want, versus what has happened or what’s wrong.”

A contract didn’t work out with Amy Chan’s ex, but she plans to use one for her next relationship.Brian Zak/NY Post

If you’re considering making a contract of your own, be sure not to turn it into a glorified chore chart, says Juliet Heeg, a therapist who is starting to see more agreements such as Kippen’s in her Upper East Side office.

Long lists filled with cleaning demands or sexual requests often just fuel nasty arguments over responsibilities, Heeg says, “[That] impairs the sense of well-being [the contract] was designed to create.”

Also, don’t hesitate to revisit the contract. Heeg suggests evaluating your demands every few months, especially during a major change in the relationship, such as getting married or having a child.

“If things don’t line up the way you hoped, revisit it,” she says.

Barillas and Sandlan recently re-evaluated their contract to reflect new changes in their relationship: moving in together and getting a puppy. Some highlights: “Charlie needs to stop judging Trish on her choices of nighttime TV”; “[Trish needs to] clean the tub after [she has] a bath, just a quick wipe-down.” It’s helped the new roomies “understand each other’s pet peeves, and who does what [around the house],” says Barillas.

Alas, such detailed accords aren’t for everyone.

Some singles, including Roland Smith, a 28-year-old West Village resident who works in banking, blanch at the idea of “killing the spark” by signing a contract.

“Usually, these things come up organically . . . after the honeymoon phase,” says Smith. “[If a woman] brought up the topic of a contract . . . I’d be scared.”